Process for purifying mineral oils



Patented Nov. 17, 1925 UNITED STATES PATENT OFFICE.

JACOB F. FABER, OF LOS ANGELES, AND HENRY C. HANNA AND MARVIN L. CHAP-IPELL, OF EL SEGUNDO, CALIFORNIA, ASSIGNORS T STANDARD OIL COMPANY, OFSAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

PROCESS FOR PURIFYING MINERAL OILS.

1T0 Drawing.

To aZL'whom it may concern:

Be it known that we, JACOB F. FABER, a

citizen of the United States, residing at I Process for PurifyingMineral Oils, of

which the following is a specification.

Our invention relates to a process for ing mineral oils.

An object of the invention is to purify a petroleum oil so as to producea treated oil which will not emulsify when commingled with water or acaustic soda solution.

Another object of the invention is to provide a process or method of sotreating petroleuin oils that an emulsion will not be formed duringtreatment thereof.

Another object ofthe invention is to produce a lubricating oil suitablefor lubricating steam turbines or other machinery in which thelubricating oil may come into contact or become commingled with water orsteam.

Another object of the invention is to produce a lubricating oilsubstantially free from einulsifying constituents.

Another object of the invention is to eliminate from a lubricating oilduring treatment thereof substantially all its emulsifying constituentsand thereby prevent a partial or complete emulsification of thelubricating oil during treatment.

Another object of the invention is to produce a lubricating oilsubstantially, free from resins, gums, organic surfo-acids.

Another object of the invention is to ac complish the above with aminimum, loss in the final yield of treated oil.

Other advantages of the invention will appear in -thepractical useof thesame and from the following description.

During the acid treatment of petroleum oil by means of sulphuric acidcertain polymerized, ox and oxy-sulfo compounds are formed w ich have apreferential oil solubility and remain in solution in the oil after theacid sludge has been separated from the oil. These compounds cannot becompletely removed from the oil by means organic acids, phenols orApplication filed 'Ianuary26, 1922. Serial No. 531,991.

of any of the well known methods of wash mg with water or neutralizingwith caustic soda. Upon any such attempt to wash the treated oil withWater or neutralize the same with caustic soda the said compounds willcause the formation of emulsions of oil and water. That portion of saidemulsifying constituents, which is removed by" neutralizing' withcaustic soda or washing with water, is emulsified with a certainpercentage ofthe treated oil and the removal thereof dimlnlshes theyield of said treated 'oil. The portion of said emulsifying constituentsremaining in the treated oil will cause the same to form emulsions whenin use, slnce the oil may come into contact; with water, or sea waterwhich is usedin the coolmg system of steam turbines. In' particular, inthe manufacture of lubricating 011s from an asphalt or mixed base crudeoil by well known methods, there is lost during the neutralizing andwashing operations from 3 to 15% by volume of the treated oil, and atbest only an imperfect separation of the emulsifying constltuents can behad.

Certain methods have been heretobefore developed with some success toemploy acid sludge or derivatives thereof as an agent to remove theabove described emulsifying constituents. perior results can be obtainedby employing a properly concentrated water solution of salt of apetroleum car'boxylic acid as an agent or solvent for extractingtheremulsifying constituents. We have also established an apparentparadox, because in We have discovered that susmall proportions ordilute solutions petroleum carboxylic compounds in fact constithe acidby means of a water solution of a metallic base from. an asphalt ormixed base crude petroleum oil, or a derivative therefrom, which hasbeen treated with'sulphuric acid or other oxidizing agent. Ihe

metallic base neutralizes the carboxylic acid to form a water solublecarboxylic salt. Also water soluble carboxylic salts may be obtained byextracting the acid from any asphalt or mixed base crude petroleum oilor derivative thereof, by treating the same with a water solution of ametallic base to neutralize the natural carboxylic acids containedtherein.

In the manufacture of lamp oils from. an asphalt or mixed base crudepetroleum oil, it is customary to treat what is known as a lamp oildistillate with relatively large amounts of fuming sulphuric acid, whichtreatment produces small amounts of a pctroleum carboxylic acid inaddition to the natural petroleum carboxylic acid contained therein.This carboxylic acid may be neutralized with a water solution of causticsoda or other metallic base. This extract is commonly known as spentcaustic solution and contains in addition to the soluble petroleumcarboxylic acid salts, certain percentages of sodium sulphite and sodiumsulphate. This sodium sulphiteand sodium sulphate does not interfere inour process and need not be removed. This said spent caustic solutionobtained in the manufacture of lamp oils, or any other spent causticsolution obtained in refining petroleum oils and containing solublepetroleum carboxylic salt, may serve as our demulsifying agent afterbeing concentrated to the required degree. The solution embodying ourdemulsifying agent should be concentrated by any well known methoduntil'it contains preferably from 5% to 25% by weight petroleumcarboxylic salts.

In practice we prefer to apply our invention by combining ourdemulsifying solution with the alkali necessary for the neutralizationof the acids remaining in an acid treated oil after separation of theacid sludge. The combined demulsifying solution and alkali may be addedto the acid treated oil and the removal of the above describedemulsifying constituents will take place simultaneously with theneutralization of the acids present in the oil. This procedure willeliminate the formation of any stable emulsion during the refiningoperation. In the refining of lubricating oils by using a quantity ofthe mixed concentrated spent caustic-soda solution and alkali equal tofrom 10 to 30% of the volume of lubricating oil to be treated theresulting mixture as previously stated preferably contains between 5% to25% petroleum carboxylic salt. The quantity of alkali present is notcritical and will depend upon the acidity of the oil to be treated. The

combined solution is added to the oil and.

agitated until commingled and is then allowed to stand at rest from 2 to16 hours at a temperature ranging preferably from that specificapplication.

approximately 130, to 180 F., or until stratification takes place; Thewater solution containing the impurities should then be drawn off andthe oil tested for emulsi fying constituents. If any of'the latter re,-main the oil should be further treated with an alkaline solution of ourdemulsifying agent. After the treated oil is found to contain no furtheremulsifying constituents, I it may be given a water or alkaline wash, ifnecessary, to remove all traces of our demulsifying solution and maythen be finished by well known methods.

In lieu of our preferred application of our invention the acid treatedoil may be first independently neutralized by an alkaline solution andthe oil thereafter treated with our demulsifying agent. Likewise the oilmay be treated by our demulsifying agentdirectly after separation of theacid sludge and prior to neutralization, so that neutralization followsrather than proceeds or occurs simultaneous to our demulsifyingtreatment.

Our demulsifying agent may be employed to remove the emulsifyingconstituents contained in finished lubricating oils which were notextracted during the refining thereof. This may be readily accomplishedby combining the finished oil and our demulsifying solution andmaintaining the mixture at proper temperature until stratification takesplace.

The petroleum carboxylic salt for the best results should be as free aspossible from neutralized sulpho acids. By obtaining these petroleumcarboxylic salts through extracting petroleum carboxylic acids by meansof a water solution of a metallic base from an asphalt or mixed basecrude petroleum oil, the resultant petroleum carboxylic salt will befree from sulpho nated salts or soaps and will be superior for thisreason for some purposes than those obtained from an oil treated withsulphuric acid.

It will be understood that with different oils different proportions,temperatures and times will give best results. The proper proportions,temperature and times may be determined for any oil by preliminarytests. Ive have endeavored to describe a specific application of ourinvention but we do not intend to limit ourselves to the details of Weclaim: 1. A process of refinmgpetroleum oils which consists in treatingan oil with sulphuric acid, separating the treated oil from the acidsludge and neutralizing the treated 11% I oil in the presence of apetroleum carboxylic salt to prevent the formation of a persistentemulsion, said petroleum carboxylic salt being obtained by extractingpetroleum carboxylic acids from crude petroleum oil by 1% means of watersolution of a metallic 'base,

oil .fromwhich the sludge has been removed.

3., A process of treating petroleum oils to prevent the formation of apersistent emulsion which consists in adding an aqueous solutioncontaining approximately 5 to of a carboxylic salt derived byextractingpetroleum carboxylic acid from crude petroleum oil by means ofa water solution of a metallic base to an acid treated oil from ,whichthe sludge has been removed and ,the treated oil neutralized.

4. A process of refining petroleum oil which consists in treating theoil with sulphuric acid, separating theacid sludge from the oil, andneutralizing the treated oil with a solution'of caustic soda'andcarboxylic salt said'carboxylic salt being derived-by extractingpetroleum carboxylic acids from crude petroleum oil by means of ametallic base, whereby a petroleum carboxylic salt is obtained .free ofsul honated soap's.

5. A process of treating petroleum oils to prevent the formation of apersistent emulsion, which consists in addinga water sol.- ublecarboxylic salt, derived by extracting petroleum carboxylic acid frompetroleum oil by means of a water solution of a metallic base, to anacid treated oil from which the sludge has been removed, the said pe'-troleum oil being free of sulfonic acids.

6. A process of refiningpetroleum oils, which consists in treating theoil with sulfuric acid, separating the acid sludge from the oil andneutralizing the treated oil with .a solution of caustic soda andcarboxylic salt, said carboxylic salt being derived by extractingcarboxylic acid from petroleum oil free of sulfonic acids by means of ametallic base, whereby a petroleum carboxylic salt is obtained free fromsulfonated soaps.

Signed at Los Angeles, California, this 20th day of January, 1922.

JAooB F. FABER.

HENRY o. HANNA. MARVIN I2. CHAPPELL

